Broadcast networks having digital video recorders provide video services that allow subscribers to order programs. A subscriber typically accesses a program library and requests a desired program. Typically, the requested program is delivered to a digital video recorder (DVR) at the subscriber location and recorded for viewing over a predetermined period of time.
Near video on demand (NVOD) service offers programs which a subscriber can choose to purchase and view at a predetermined time. The programs have regular start times, for example every half-hour, and a subscriber enjoys the purchased program at scheduled times. NVOD services have hardware based encryption methods applied to the digital broadcast signal, making them difficult to defeat, thereby limiting access to the programming to purchasers only. Impulse pay per view (IPPV) programming is another type of NVOD but allows a subscriber to purchase the program using their remote control.
Video on demand (VOD) service provides a subscriber with virtually instantaneous access to the program for viewing. The customer doesn't have to wait for a scheduled start time before viewing the program. For customers with a DVR, the VOD service can be offered by delivering a collection of programs a priori, or without a specific request, to a subscriber's DVR and then offering those programs for purchase and viewing upon the subscriber's demand virtually independent of a scheduled viewing time.
However, the added advantage of purchasing and watching a program without having to request the program in advance is not without significant drawbacks. The subscriber's DVR has limited storage capacity and therefore, the quantity of programs stored on the DVR is limited to the DVR's available storage capacity. Therefore, to store all available programming choices results in unpurchased and unwanted programming being unnecessarily stored on the customer's DVR.
Another drawback associated with video on demand service is the security risk associated with delivering and storing the program content. Typically, the program content stored on the DVR is encrypted using software based encryption methods. A hacker can defeat the software based encryption methods of the stored programs, increasing the risk that the program content may be accessed without actually being purchased. Yet another drawback is the need to store the encrypted data on the DVR. For many VOD applications, a DVR must have the capability to store encrypted video, which is a feature that not all DVR's possess. This severely limits the availability of VOD services.
There is a need to provide VOD services while maintaining the security and wide variety of available program content associated with NVOD services.